JP2008044439A - Motor and in-wheel motor structure using same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To supply an appropriate amount of oil to a bearing supporting a motor shaft by devising the shape of the motor shaft. <P>SOLUTION: The motor 700 structured so that a fluid can be supplied to the motor shaft 710 from above a motor case (430) is provided with bearings 820, 830 supporting the motor shaft 710 rotatably. In the parts 712, 714, 716, 718 of the motor shaft not supported directly by the bearings 820, 830, small diameter parts 714, 716 with diameters smaller than those of parts 712, 718 axially contacted with the bearings are provided. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a motor and an in-wheel motor structure using the same.

2. Description of the Related Art Conventionally, an in-wheel motor structure is known that includes an oil pump that is operated by the rotational output of a motor and includes an oil passage that supplies oil from the oil pump to the outer periphery of a stator core of the motor (see, for example, Patent Document 1). ). In this in-wheel motor structure, the oil supplied from the outer periphery of the stator core of the motor is used for cooling the stator core and the stator coil, and is then used for lubricating each bearing that supports the shaft of the motor and the reduction gear.
JP 2005-73364 A

  By the way, although a large amount of oil is required for cooling the stator core and the stator coil, a small amount of oil is sufficient for lubricating the bearing. On the other hand, if a large amount of oil is applied to the bearing, rotation loss occurs and efficiency is reduced.

  Accordingly, an object of the present invention is to devise the shape of the motor shaft so that an appropriate amount of oil is supplied to the bearing that supports the motor shaft.

To achieve the above object, the first invention is a motor configured to be able to supply fluid to the motor shaft from above the motor case.
It has a bearing that rotatably supports the motor shaft,
The motor shaft portion that is not directly supported by the bearing is provided with a small-diameter portion having a diameter smaller than the diameter of the portion that abuts the bearing in the axial direction.

In order to achieve the above object, a second invention relates to an in-wheel motor structure,
A wheel driving motor comprising a motor shaft disposed in a wheel and rotatably supported by a bearing;
An oil pump that operates according to the rotational output of the motor;
An oil flow path for guiding oil from the oil pump to a motor shaft of the motor;
The motor shaft portion that is not directly supported by the bearing is provided with a small diameter portion having a diameter smaller than the diameter of the portion that abuts the bearing in the axial direction.

  According to the present invention, an appropriate amount of oil can be supplied to the bearing that supports the motor shaft.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 is a cross-sectional view showing a main configuration of an in-wheel motor structure according to an embodiment of the present invention. In FIG. 1, the illustration of the upper one-third portion of the wheel is omitted, and the illustration of the tire is also omitted.

  The wheel 10 includes a wheel 14 to which a tire (not shown) is attached. In the space surrounded by the rim inner peripheral surface 14 a of the wheel 14, as will be described in detail below, main portions of motor-related components are housed. In the present specification and the appended claims, “in the wheel” means a substantially cylindrical space surrounded by the rim inner peripheral surface 14 a of the wheel 14. However, an expression such as that a part is placed in a wheel does not necessarily mean that the entire part is completely contained in the substantially cylindrical space, and a part of the part is partially omitted. It does not exclude a configuration that protrudes from the cylindrical space.

  Inside the wheel 10 are mainly an axle bearing 100, a brake disc 110, a brake dust cover 112 that covers the brake disc 110 from the inside of the vehicle, a brake caliper (not shown), and a motor 700 for driving the wheel. The speed reduction mechanism 200, the oil pump 300, the oil tank (oil sump) 310, the oil flow path (described later), the knuckle (carrier) 400, and the lower ball joint to which the wheel side end of the lower arm 520 is connected. 500 is arranged. Although not shown in the figure, a ball joint to which a wheel side end of a tie rod (not shown) is connected and an upper ball joint to which a wheel side end of an upper arm is connected are arranged in the wheel 10. . However, in the case of the strut suspension, the lower end of the strut (shock absorber) is connected to the upper side of the knuckle 400 instead of the upper arm.

  The motor 700 is disposed in a space inside the vehicle inside the wheel 10. As shown in FIG. 1, the motor 700 is arranged offset to the upper side with respect to the axle center, and is arranged to be offset to the front side of the vehicle with respect to the axle center (see FIG. 2). Thereby, in the space inside the vehicle in the wheel 10, as shown in FIG. 1, a space that is not occupied by the motor 700 is created on the vehicle rear side and the lower side by an amount corresponding to the offset of the motor 700. Therefore, compared to a configuration in which the motor is concentrically arranged around the axle center, the space on the vehicle inner side and the lower side in the wheel 10 is widened, so that the degree of freedom in arranging the suspension on the lower side is increased. Moreover, in the wheel 10, it can be easily mounted on the brake caliper on the side (vehicle rear side) opposite to the side where the motor 700 is offset (in this example, the vehicle front side) (the brake caliper attachment in FIG. 2). (See point 122).

  Main components of the motor 700 include a stator core 702 made of a laminate of electromagnetic steel plates (for example, silicon iron), a stator coil 704 wound around a groove (iron core groove) of the stator core 702, and a rotor 706. The motor 700 is disposed such that the rotation axis of the rotor 706 is offset with respect to the axle center as described above. When motor 700 is a three-phase motor, stator coil 704 includes a U-phase coil, a V-phase coil, and a W-phase coil. The rotor 706 is disposed on the inner peripheral side of the stator core 702 and the stator coil 704.

  As shown in FIG. 1, the rotor 706 includes a motor shaft 710 having a circular cross section that constitutes a rotating shaft, an outer peripheral portion 722 that is opposed to the stator core 702 in the radial direction, an outer peripheral portion 722, and the motor shaft 710 in the radial direction. And a connecting portion 720 connected to the. A ring-shaped space 730 is formed around the motor shaft 710 between the outer peripheral portion 722 and the motor shaft 710. The space 730 is partitioned by a connecting portion 720 into a first space 732 inside the vehicle and a second space 734 outside the vehicle. In the first space 732, a peripheral wall 752 protruding from the vehicle outer surface of the motor cover 750 is accommodated with an appropriate gap. The outer ring side of the bearing 820 is coupled to the inner peripheral side of the peripheral wall 752 by caulking or the like.

  The motor shaft 710 is provided with a bearing 820 in the vicinity of the inner end of the vehicle. The bearing 820 may be a radial ball bearing (ball bearing) using balls as rolling elements, and may be, for example, a single row deep groove ball bearing. The outer ring side of the bearing 820 is coupled to the peripheral wall 752 of the motor cover 750. As a result, the motor shaft 710 is rotatably supported by the motor cover 750 via the bearing 820 inside the vehicle in the wheel 10.

  In the first space 732, the motor shaft 710 is adjacent to a portion 719 directly supported by the bearing 820, between the portion 718 that is in radial contact with the inner ring of the bearing 820, and between the portion 718 and the connecting portion 720. And 716. The portion 718 is a circular section having an outer diameter substantially corresponding to the outer diameter of the inner ring of the bearing 820, and is hereinafter referred to as a “first large diameter portion 718”. The part 716 is a circular part having a smaller diameter than the first large diameter part 718, and is hereinafter referred to as a “first small diameter part 716”. The bearing 820 is responsible for the thrust load input via the first large diameter portion 718 together with the radial load. The technical significance of the first large diameter portion 718 and the first small diameter portion 716 will be described later in relation to the oil flow path.

  The motor shaft 710 is provided with a bearing 830 in the vicinity of the outer end of the vehicle. The bearing 830 may be a radial ball bearing (ball bearing) using balls as rolling elements, for example, a single row deep groove ball bearing. The outer ring side of the bearing 830 is coupled to the knuckle 400. Thereby, the motor shaft 710 is rotatably supported by the knuckle 400 via the bearing 830 on the outside of the vehicle.

  Similarly, in the second space 734, the motor shaft 710 is adjacent to a portion 711 that is directly supported by the bearing 830, a portion 712 that is in radial contact with the inner ring of the bearing 830, a portion 712, and a connecting portion. And 720 between 720. The portion 712 is a circular section having an outer diameter substantially corresponding to the outer diameter of the inner ring of the bearing 830 and is hereinafter referred to as a “second large diameter portion 712”. The portion 714 is a circular section having a smaller diameter than the second large diameter portion 712, and is hereinafter referred to as a “second small diameter portion 714”. The bearing 830 is responsible for the thrust load input through the second large diameter portion 712 together with the radial load. The technical significance of the second large diameter portion 712 and the second small diameter portion 714 will be described in detail later in connection with the oil flow path.

  The rotation output of the motor 700 is transmitted to the wheel 14 via the speed reduction mechanism 200. The speed reduction mechanism 200 is a two-axis speed reduction mechanism, and includes a counter gear mechanism 210 and a planetary gear mechanism 220, and realizes two-stage speed reduction. In addition, each gear 212, 214, 222, 224, 226, 228 of the speed reduction mechanism 200 described below may be constituted by a helical gear.

  As shown in FIG. 1, the counter gear mechanism 210 is disposed outside the motor 700. The counter gear mechanism 210 includes a small-diameter drive gear 212 disposed coaxially with the output shaft 710 of the motor 700 and a large-diameter driven gear (counter gear) 214 that meshes with the drive gear 212. The small-diameter drive gear 212 is spline-fitted from the vehicle outer side to the vehicle outer end portion of the motor shaft 710 of the motor 700 (portion outside the portion 711), and is caulked and integrated. The large-diameter counter gear 214 has a center of rotation about the axle. Therefore, the motor shaft 710 of the motor 700 is disposed offset from the axle center by a distance obtained by adding the radius of the drive gear 212 and the radius of the counter gear 214.

  As shown in FIG. 1, the planetary gear mechanism 220 is disposed on the vehicle outer side than the counter gear mechanism 210 in a space outside the vehicle in the wheel 10. The planetary gear mechanism 220 is disposed coaxially with the axle center. The planetary gear mechanism 220 includes a sun gear 222, a planetary gear 224, a planetary carrier 226, and a ring gear 228.

  The sun gear 222 is connected to the counter gear 214 of the counter gear mechanism 210. In the example shown in FIG. 1, the sun gear 222 and the counter gear 214 are formed at both ends of the sun gear shaft (shaft) 250 in the vehicle inside / outside direction. Specifically, the sun gear shaft 250 has a center of rotation about the axle, has a sun gear 222 on the outer peripheral surface of the vehicle, and a counter gear 214 on the peripheral surface of the inner side of the vehicle. The sun gear shaft 250 is rotatably supported on the knuckle 400 via a bearing 800 at the end on the inner side of the vehicle, and is supported on the disc-shaped power transmission member 270 via a bearing 810 on the end on the outer side of the vehicle. And is rotatably supported. Note that the sun gear 222 and the counter gear 214 may be configured as separate parts, and in this case, the respective parts may be splined together. Further, the bearing 800 and the bearing 810 may be radial ball bearings (ball bearings) using balls as rolling elements, for example, single row deep groove ball bearings. Further, as shown in FIG. 1, the bearing 800 may be incorporated in the counter gear 214 (inner peripheral side), and the convex portion 412 of the knuckle 400 is coupled to the inner ring side of the bearing 800 by press fitting or the like. .

  The planetary gear 224 meshes with the sun gear 222 on the inner peripheral side and meshes with the ring gear 228 on the outer peripheral side. The planetary gear 224 is rotatably supported with respect to the planetary carrier 226 via a roller bearing 225. The planetary carrier 226 has a center of rotation about the axle, and is supported on the sun gear shaft 250 via a thrust cylindrical roller bearing 840 on the vehicle inner side in the wheel 10, and is circumferentially formed on the power transmission member 270 on the vehicle outer side. Is spline-fitted into the circumferential groove 272 formed in A plurality of planetary gears 224 are set around the sun gear 222 at equal intervals. The planetary gear 224 and the planetary carrier 226 are assembled to form one unit (hereinafter referred to as “planetary gear unit”). The planetary carrier 226 of the planetary gear unit abuts against the stopper portion 274 of the power transmission member 270 on the outside of the vehicle. As a result, the planetary gear unit is restricted from being displaced in and out of the vehicle by the thrust cylindrical roller bearing 840 and the stopper portion 274.

  Ring gear 228 has a center of rotation about the axle, and is formed on the inner peripheral surface of inner ring side member 260 arranged to surround sun gear 222 from the outer peripheral side. The outer peripheral surface of the inner ring side member 260 constitutes an inner race of the axle bearing 100. In the illustrated example, the axle bearing 100 is a two-row angular ball bearing, and the outer inner race for the outer row of the vehicle is constituted by a member different from the inner ring side member 260. Such another member is integrated with the inner ring side member 260 by being fitted to the outer periphery of the inner ring side member 260 and caulked.

  The outer ring side member 262 is disposed so as to surround the inner ring side member 260 from the outer peripheral side. An inner peripheral surface of the outer ring side member 262 constitutes an outer race of the axle bearing 100. Seals 280 and 282 are provided at the end portion in the vehicle inside / outside direction between the outer ring side member 262 and the inner ring side member 260 to prevent foreign matters from entering and oil to flow.

  The power transmission member 270 is a disk-shaped member provided so as to cover the vehicle outer side of the speed reduction mechanism, and a circumferential groove 272 in which the vehicle outer end portion (peripheral wall portion) of the planetary carrier 226 is spline-fitted on the vehicle inner side. Is formed. The outer peripheral edge of the power transmission member 270 is coupled to the end of the outer wheel side member 262 on the vehicle outer side by caulking or the like. That is, the power transmission member 270 is fixed to the outer ring side member 262 so as to close the substantially circular opening of the outer ring side member 262 outside the vehicle. The outer ring side member 262 has a flange portion (flange portion) 263 that protrudes radially outward on the outer peripheral surface, and a bolt hole in which the hub bolt 264 is fastened is formed in the flange portion 263. The outer ring side member 262 is fastened together with the brake disc 110 to the wheel 14 with a hub bolt in a state where the inner peripheral portion of the brake disc 110 is sandwiched between the flange portions 263.

  In the above configuration, when the rotor 706 of the motor 700 is rotated by a command from a vehicle control device (not shown), the small-diameter driving gear 212 of the counter gear mechanism 210 is rotated accordingly, and the large-diameter counter meshing with the driving gear 212 is rotated. The gear 214 rotates and the first-stage deceleration is realized. When the counter gear 214 rotates, the sun gear 222 integrated with the counter gear 214 rotates, and accordingly, the planetary gear 224 rotates around the sun gear 222 while rotating. The second stage of deceleration is realized by this rotation. The revolution movement of the planetary gear 224 is taken out by the planetary carrier 226 and transmitted to the power transmission member 270 that is spline-fitted to the planetary carrier 226. Thus, when the power transmission member 270 is rotated, the outer ring side member 262, the brake disc 110, and the wheel 14 rotate together with the power transmission member 270. That is, driving of the wheels is realized.

  The knuckle 400 mainly includes a main structure portion 410 located near the center of the wheel 10 and a cylindrical peripheral wall portion (motor case portion) 430. The main components of the motor 700 described above are disposed in the radially inner space of the peripheral wall portion 430 of the knuckle 400. A motor cover 750 is coupled to a vehicle inner end of the peripheral wall portion 430 of the knuckle 400 so as to cover a space in the peripheral wall portion 430. A gasket (not shown) for preventing oil leakage may be provided at the joint between the peripheral wall 430 and the motor cover 750.

  Unlike the thin peripheral wall 430 and other ribs, the main structure 410 of the knuckle 400 has sufficient strength and rigidity, and is connected to the axle bearing 100, tie rod, suspension arm (lower arm 520, etc.). It plays the role which takes charge of the load input via the point and the brake caliper attachment point 122 (refer FIG. 2).

  An inner ring side member 260 is coupled to the end of the main structure 410 of the knuckle 400 on the vehicle outer side by, for example, press fitting or bolts. An O-ring 910 for preventing oil leakage may be provided at the joint between the knuckle 400 and the main structure 410.

  The main structural portion 410 of the knuckle 400 is responsible for various loads input from the wheels 10 through the axle bearing 100 (inner ring side member 260) at the end on the vehicle outer side. The counter gear mechanism 210 is disposed in the internal space of the main structure 410 of the knuckle 400. The main structure 410 of the knuckle 400 is responsible for various thrust loads and radial loads input via the bearings 830 and 800. Since the main structure 410 of the knuckle 400 has high rigidity, it is desirable to set the dynamic rated load or dynamic equivalent load of the bearings 830 and 800 higher than the corresponding bearings 820 and 810, respectively. As a result, a rational structure capable of receiving a large load on a portion having high strength and rigidity is realized.

  The main structure 410 of the knuckle 400 has two arms 424 and 426 (see FIG. 2) extending downward. The knuckle arm 130 is fastened to the lower ends of the arm portions 424 and 426 by bolts or the like. The knuckle arm 130 extends in the vehicle front-rear direction within the wheel 10. A ball joint for attaching a tie rod is set on the front end side of the knuckle arm 130, and a lower ball joint 500 is set on the rear end side of the knuckle arm 130. The main structure 410 of the knuckle 400 is responsible for various loads that are input via the lower ball joint 500 or the like.

  As shown in FIG. 1, the lower ball joint 500 is disposed on the vehicle inner side than the brake disc 110. A lower arm 520 is fastened to the lower ball joint 500 by a nut 522 from above. The lower arm 520 extends in the vehicle width direction, and an end portion on the inner side of the vehicle is supported by a vehicle body (not shown) via a bush or the like. The lower arm 520 may be of any type, for example, an L-shaped lower arm or a double link type lower arm. The lower arm 520 cooperates with an upper arm (or strut) (not shown) and supports the wheel 10 so as to be swingable with respect to the vehicle body. A spring and an absorber (not shown) are provided between the vehicle body and the lower arm 520. Thereby, the input to the vehicle body from the wheel 10 is eased. The spring may be of any type such as a spring coil or an air spring, and the absorber also has a damping action on the rotational input in addition to a hydraulic absorber that gives a damping action on the vertical input. A rotating electromagnetic absorber may be used.

  In this embodiment, since the motor 700 is offset upward with respect to the axle center as described above, the degree of freedom in the arrangement position of the lower ball joint 500 (arrangement of the kingpin shaft) is increased. As shown in FIG. 1, the brake disc 110 can be made as close as possible to the maximum while leaving a necessary clearance. As a result, the offset between the tire input point and each member in the vehicle inside / outside direction is reduced, so that the required strength and rigidity of each member (for example, the main structure portion 410 of the knuckle) can be reduced and the weight can be reduced. .

  As shown in FIG. 1, the oil tank 310 is formed below the knuckle 400 and is disposed on the lower side on the vertical line intersecting the axle center in the wheel 10. The oil tank 310 is preferably disposed below the lowest position of the gear portion of the speed reduction mechanism 200. Further, as shown in FIG. 1, the oil tank 310 is disposed on the vehicle outer side than the lower ball joint 500 and is disposed on the vehicle inner side than the brake dust cover 112.

  The oil tank 310 is disposed using the internal space of the hat portion 110 a of the brake disc 110. In the illustrated example, the oil tank 310 is formed by a cover member 311 that is fixed to the knuckle 400 from the outside of the vehicle. The cover member 311 may be coupled to the knuckle 400 by caulking, bolts, or the like. According to such a configuration, the oil tank 310 is disposed so as to be completely offset with respect to the lower ball joint 500 in the vehicle inside / outside direction. As a result, even if oil leaks from the oil tank 310 due to damage to the oil tank 310 or the like, the leaked oil is reliably prevented from being applied to the lower ball joint 500, and the performance of the lower ball joint 500 is reduced. Can be reliably prevented.

  The oil tank 310 is connected to the lower end of the suction path 312 that is also formed in the knuckle 400 and communicates with an oil return path 313 for oil return. The oil tank 310 serves to store oil for cooling the motor 700 or lubricating the speed reduction mechanism 200 as described above.

  Further, the oil tank 310 communicates with a drain channel 314 and a filler channel 316 (see FIG. 2) formed in the knuckle 400. The respective openings of the drain channel 314 and the filler channel 316 are closed by a drain plug and a filler plug (not shown).

  The oil pump 300 is disposed between the motor 700 and the planetary gear mechanism 220 of the speed reduction mechanism 200 in the vehicle inside / outside direction. Specifically, the oil pump 300 is provided at the end of the sun gear shaft 250 on the vehicle inner side. In the example shown in FIG. 1, the oil pump 300 is disposed inside the counter gear 214 of the counter gear mechanism 210, that is, inside the counter gear 214 in the radial direction. More specifically, the convex portion 412 of the knuckle 400 is housed in the cavity 252 on the radially inner side of the end portion on the vehicle inner side of the sun gear shaft 250 (the enlarged diameter portion for forming the counter gear 214). The oil pump 300 is provided in the recess 413 on the end surface (vehicle inner surface) of the portion 412. The inside of the recess 413 and the periphery of the pump rotation shaft 302 extending into the recess 413 are sealed by a seal member 305.

  The oil pump 300 may be any type of gear pump, such as an external gear pump, an internal gear pump (with or without crescent), as well as a trochoid pump as shown in the figure, and other types such as a vane pump. The hydraulic pump may be used.

  Oil pump 300 is operated by the rotational output of motor 700. Specifically, the inner rotor of the oil pump 300 is connected to a pump rotation shaft 302 that is integral with the sun gear shaft 250 and is rotated by the rotation of the sun gear shaft 250. That is, the inner rotor of the oil pump 300 is driven coaxially with the counter gear 214. When the inner rotor is rotated, the outer rotor whose rotation axis is eccentric with respect to the inner rotor is rotated. As a result, the oil in the oil tank (reservoir tank) 310 is pumped up via the suction path 312, and the oil sucked from the suction port 304 (see FIG. 2) is placed between the outer rotor and the inner rotor of the oil pump 300. It is sandwiched and pumped and discharged from the discharge port 306 (see FIG. 2) to the oil flow path. The oil flow path will be described later.

  In the present embodiment, as described above, the oil pump 300 is driven by the rotational output of the counter gear 214, so that the oil pump 300 is decelerated by the counter gear mechanism 210 as compared with the rotational speed of the motor 700. Driven at a low rotational speed. Thereby, compared with the case where it drives coaxially with the motor shaft 710 of the motor 700, the maximum rotation speed of the oil pump 300 becomes low, and the durability of the oil pump 300 improves.

  Further, in the present embodiment, as described above, the oil pump 300 is set inside the sun gear shaft 250 and is disposed within the same range as the counter gear mechanism 210 in the inside and outside of the vehicle. The length in the axle direction necessary for the arrangement of the oil pump 300 and the speed reduction mechanism 200 can be shortened by the amount of the oil pump 300 compared to the case where the motor, the oil pump and the speed reduction mechanism are arranged in series.

  In the present embodiment, as described above, the oil pump 300 is disposed in the middle between the motor 700 and the speed reduction mechanism 200. Therefore, the cooling or speed reduction mechanism 200 of the motor 700 and various bearings (bearings 800, 810, 820, 830, etc.) is easy to arrange the oil flow path.

  Next, main oil flow paths that the oil discharged from the oil pump 300 follows will be described.

  An oil passage 910 formed inside the sun gear shaft 250 communicates with the discharge port 306 (see FIG. 2) of the oil pump 300. The oil discharged from the discharge port 306 to the oil flow path 910 is supplied to the bearing 810 through the opening 914 at the tip end portion of the sun gear shaft 250, and through the oil hole 912 by centrifugal force when the sun gear shaft 250 rotates. And supplied to the planetary gear 224. The oil thus supplied is used for lubrication of the bearing 810 and the roller bearing 255 at the rotation center of the planetary gear 224.

  FIG. 2 is an explanatory view of each oil flow path for cooling the motor 700 and lubricating the bearings 820, 830, and 800, with the motor cover 750 and the internal elements of the motor 700 removed, the peripheral wall portion of the knuckle 400 (motor It is the top view seen from the vehicle inner side which shows the inside of (case part) 430. In FIG. 2, illustrations of less relevant members are omitted as appropriate for the explanation of the oil flow path.

  An oil flow path 920 (see also FIG. 1) provided using a space near the coil end communicates with the discharge port 306 of the oil pump 300. As shown in FIG. 2, the oil flow path 920 circulates around the coil end at a corner near the base of the peripheral wall 430 of the knuckle 400. The oil channel 920 may be formed inside the knuckle 400, but is preferably formed by a member 930 different from the knuckle 400 (hereinafter referred to as “oil delivery 930”). The oil delivery 930 has a tubular cross section, and is formed of, for example, an elastic member. As shown in FIG. 1, the oil delivery 930 is disposed so as to be in close contact with the bottom surface 414 of the knuckle 400 and the vehicle outer end surface of the stator core 702.

  The oil delivery 930 is formed with a distribution hole 932 that opens radially outward at an angular position with an appropriate interval in the circumferential direction. An oil groove 432 extending in the axial direction is formed at each angular position corresponding to the distribution hole 932 on the inner peripheral surface of the peripheral wall portion 430 of the knuckle 400.

  In addition, as shown in FIG. 2, the oil delivery 930 is formed with a distribution hole 933 that opens radially inward at an angular position at an appropriate interval in the circumferential direction. In the illustrated example, the distribution hole 933 is formed at the same angular position as the distribution hole 932, but the set number and angular position may be different from the distribution hole 932.

  Further, the oil delivery 930 has a bearing distribution hole 934 formed in the vicinity of an angular position in the circumferential direction that intersects with the position where the bearing 800 is arranged in the axial direction. The bearing distribution hole 934 opens in the axial direction (perpendicular to the paper surface) toward the bearing 800.

  As shown by the arrow P1 in FIG. 2, the oil discharged from the discharge port 306 to the oil flow path 920 (the flow path in the oil delivery 930) is pumped around the coil end as shown by the arrow P2 in FIG. The In the process, a part of the oil is supplied to the bearing 800 through the bearing distribution hole 934 and is used for lubricating the bearing 800. Further, as shown by an arrow P <b> 3 in FIG. 2, the other oil is discharged radially outward and inward from the oil delivery 930 through the plurality of distribution holes 932 and the distribution holes 933. The oil discharged into the oil groove 432 through the distribution hole 932 is directed along the extending direction of the oil groove 432, is applied to the entire outer peripheral surface of the stator core 702, and is used for cooling the entire stator core 702. . Similarly, the oil discharged through the distribution hole 933 is directly applied to the coil end of the stator core 702 and used for cooling the entire stator coil 704 including the coil end.

  The oil supplied into the motor 700 through the distribution holes 933 and 932 flows downward from the outer peripheral sides of the stator core 702 and the stator coil 704 as shown by arrows P4 and P5 in FIG. While cooling 702, the stator coil 704, etc., it reaches the motor shaft 710 of the motor 700 and is used for lubrication of both the bearings 820 and 830 inside and outside the vehicle. The oil used for cooling or lubrication in this way is eventually returned to the oil tank 310 by gravity.

  Here, referring again to FIG. 1, the motor shaft 710 includes the first large-diameter portion 718 and the first small-diameter portion 716 adjacent to the bearing 820 in the first space 732 as described above. Therefore, the oil introduced into the first space 732 through the distribution hole 932 and the oil groove 432 as described above falls from the peripheral wall 752 of the motor cover 750 to the first large diameter portion 718 according to the arrow P5 in FIG. To do. At this time, most of the oil dropped to the first large diameter portion 718 due to the step defined by the first large diameter portion 718 and the first small diameter portion 716 follows the first large diameter portion according to the arrow P6 in FIG. It flows from 718 to the first small diameter portion 716 and passes through as it is. That is, only a part of the oil introduced into the first space 732 enters the bearing 820 from the outside of the vehicle through a gap between the inner ring and the outer ring of the bearing 820, and is used for lubrication of the bearing 820. .

  Similarly, the motor shaft 710 includes the second large diameter portion 712 and the second small diameter portion 714 adjacent to the bearing 830 in the second space 734 as described above. Accordingly, as described above, the oil introduced into the second space 734 through the distribution hole 933 through the space between the bottom surface 414 of the knuckle 400 and the stator coil 704 follows the second large diameter portion according to the arrow P4 in FIG. Fall to 712. At this time, most of the oil dropped to the second large diameter portion 712 due to the step defined by the second large diameter portion 712 and the second small diameter portion 714 follows the second large diameter portion according to the arrow P7 in FIG. It flows from 712 to the second small diameter portion 714 and passes through as it is. That is, only a part of the oil introduced into the second space 734 enters the bearing 830 from the inside of the vehicle through the gap between the inner ring and the outer ring of the bearing 830, and is used for lubrication of the bearing 830. .

  By the way, cooling of the stator core 702 and the stator coil 704 requires a large amount of oil, and it is necessary to supply the oil at, for example, 1 to 3 L / min. On the other hand, only a small amount of oil is required to lubricate the bearings 820 and 830 on both sides of the motor shaft 710. For example, the oil may be supplied at several cc / min. , 830 rotation loss, which may cause a reduction in efficiency.

  On the other hand, according to the present embodiment, as described above, by setting the first large diameter portion 718 and the first small diameter portion 716 adjacent to the bearing 820, the excess oil is lowered downward with respect to the bearing 820. You can pass through. Therefore, even when a large amount of oil is used for cooling the stator core 702 and the stator coil 704, it is possible to effectively prevent the excessive oil from being supplied to the bearing 820 due to this. That is, according to the present embodiment, only an appropriate amount of oil used for cooling the stator core 702 and the stator coil 704 can be supplied to the bearing 820, and the efficiency is reduced due to the rotation loss in the bearing 820. Can be prevented.

  Similarly, according to the present embodiment, as described above, by setting the second large diameter portion 712 and the second small diameter portion 714 adjacent to the bearing 830, the excess oil is lowered below the bearing 830. You can pass through. Therefore, even when a large amount of oil is used for cooling the stator core 702 and the stator coil 704, it is possible to effectively prevent the excessive oil from being supplied to the bearing 830 due to this. That is, according to this embodiment, only an appropriate amount of oil used for cooling the stator core 702 and the stator coil 704 can be supplied to the bearing 830, and the efficiency is reduced due to rotation loss in the bearing 830. Can be prevented.

  In this embodiment, the difference in diameter between the first large diameter portion 718 and the first small diameter portion 716 (that is, the height of the step) is the amount of oil introduced into the first space 732, and It may be determined appropriately based on the relationship with the amount of oil required to lubricate the bearing 820. For example, as the amount of oil introduced into the first space 732 becomes larger than the amount of oil necessary for the lubrication of the bearing 820, the height of the step is increased so that a larger amount of oil passes through downward. It's okay. The height of the step between the second large diameter part 712 and the second small diameter part 714 may be set similarly.

  The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the present invention. Can be added.

  For example, in the illustrated example, as a preferred embodiment, the first large-diameter portion 718, the first small-diameter portion 716, the second large-diameter portion 712, and the second are provided for both bearings 820 and 830 on both sides of the motor shaft 710. Although the small diameter part 714 is set, the same large diameter part and small diameter part may be set only for one of the bearings 820 and 830.

  In the illustrated example, the first small-diameter portion 716 and the second small-diameter portion 714 are formed to have a substantially constant diameter except for a corner bent portion (R portion), but have a smaller-diameter portion. Alternatively, for example, it may have an inclination that the diameter decreases as the distance from the large diameter portion increases.

  In the illustrated example, the diameters of the first large-diameter portion 718 and the second large-diameter portion 712 substantially correspond to the diameters of the inner rings of the corresponding bearings 820 and 830, but the oil to the bearings 820 and 830 In order to further reduce the supply amount, the diameters of the first large-diameter portion 718 and the second large-diameter portion 712 may be made smaller than the diameters of the inner rings of the bearings 820 and 830. That is, a step may be set between the first large-diameter portion 718 and the bearing 820 and between the second large-diameter portion 712 and the inner ring of the bearing 830 so that the inner ring side becomes higher.

  In addition, the illustrated example relates to the configuration of the motor 700 when applied to an in-wheel motor structure as a preferred embodiment, but as long as it is a motor that requires oil (or other fluid) for cooling, The present invention can be similarly applied to motors of other types or other arrangement locations.

It is sectional drawing which shows the main structures of the in-wheel motor structure which concerns on one Example of this invention. It is a figure which shows each oil flow path for cooling of the motor 700, and lubrication of the bearings 820,830,800.

Explanation of symbols

10 wheel 14 wheel 14a rim inner peripheral surface 100 axle bearing 110 brake disc 110a hat portion 112 brake dust cover 122 attachment point of brake caliper 130 knuckle arm 200 reduction mechanism 210 counter gear mechanism 212 drive gear 214 counter gear 220 planetary gear mechanism 222 sun gear 224 Planetary gear 225 Roller bearing 226 Planetary carrier 228 Ring gear 250 Sun gear shaft 260 Inner ring side member 262 Outer ring side member 270 Power transmission member 272 Circumferential groove 280, 282 Seal 300 Oil pump 302 Pump rotating shaft 310 Oil tank 312 Suction path 313 Oil feedback Path 400 Knuckle 410 Knuckle main structure part 412 Convex part 424, 426 Arm part 43 Peripheral wall 432 Oil groove 500 Lower ball joint 520 Lower arm 522 Nut 700 Motor 702 Stator core 704 Stator coil 706 Rotor 710 Motor shaft 750 Motor cover 800, 810, 820, 830 Bearing 840 Thrust cylindrical roller bearing 910, 920 Oil burr 930 Oil flow 930 932 Distribution hole 933 Distribution hole 934 Bearing distribution hole

Claims (2)

In a motor configured to be able to supply fluid to the motor shaft from above the motor case,
It has a bearing that rotatably supports the motor shaft,
A motor having a small-diameter portion having a diameter smaller than a diameter of a portion of the motor shaft that is not directly supported by the bearing in an axial direction against the bearing. A wheel driving motor comprising a motor shaft disposed in a wheel and rotatably supported by a bearing;
An oil pump that operates according to the rotational output of the motor;
An oil flow path for guiding oil from the oil pump to a motor shaft of the motor;
An in-wheel motor structure characterized in that a small-diameter portion having a diameter smaller than a diameter of a portion that abuts the bearing in the axial direction is provided in a portion of the motor shaft that is not directly supported by the bearing.

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